Fix wheel event dispatch logic to fallback to document when hit-test fails

LayoutTests/fast/events/dispatch-mouse-events-to-window-always-expected.txt

Index: LayoutTests/fast/events/dispatch-mouse-events-to-window-always-expected.txt
diff --git a/LayoutTests/fast/events/dispatch-mouse-events-to-window-always-expected.txt b/LayoutTests/fast/events/dispatch-mouse-events-to-window-always-expected.txt
new file mode 100644
index 0000000000000000000000000000000000000000..6296f831da848bef313e7824040076f5dcf0bd3a
--- /dev/null
+++ b/LayoutTests/fast/events/dispatch-mouse-events-to-window-always-expected.txt
@@ -0,0 +1,29 @@
+Test that wheel and mouse events are dispatched to document and window even if they do not hit any element in the page.
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+
+eventType: wheel
+PASS dispatchCount[window][eventType] is 4
+PASS dispatchCount[document][eventType] is 4
+FAIL dispatchCount[document.body][eventType] should be 2. Was 0.

[Rick Byers, 2015/06/26 12:34:48]

You've got FAILs here

[majidvp, 2015/06/29 16:58:40]

Acknowledged.

[majidvp, 2015/06/30 15:33:03]

Done.

+FAIL dispatchCount[document.getElementById("child")][eventType] should be 1. Was 0.
+eventType: click
+PASS dispatchCount[window][eventType] is 4
+PASS dispatchCount[document][eventType] is 4
+FAIL dispatchCount[document.body][eventType] should be 2. Was 0.
+FAIL dispatchCount[document.getElementById("child")][eventType] should be 1. Was 0.
+eventType: mousedown
+PASS dispatchCount[window][eventType] is 4
+PASS dispatchCount[document][eventType] is 4
+FAIL dispatchCount[document.body][eventType] should be 2. Was 0.
+FAIL dispatchCount[document.getElementById("child")][eventType] should be 1. Was 0.
+eventType: mouseup
+PASS dispatchCount[window][eventType] is 4
+PASS dispatchCount[document][eventType] is 4
+FAIL dispatchCount[document.body][eventType] should be 2. Was 0.
+FAIL dispatchCount[document.getElementById("child")][eventType] should be 1. Was 0.
+PASS successfullyParsed is true
+
+TEST COMPLETE
+